Polysulfonamide matrices

ABSTRACT

Sulfonamide polymer matrices and their various uses are disclosed. Among the uses is the configuration of the matrix with a porous support membrane to form a semipermeable membrane of the invention. The matrix of the invention is ultrathin, dense and substantially free of defects. The matrix configuration as the semipermeable membrane shows improved permeate flux and retention values.

RELATED APPLICATIONS

[0001] This application is a continuation under 35 U.S.C. 111 (a) ofInternational Application No. PCT/US01/16897 filed May 23, 2001 andpublished as WO 01/91873 A2 on Dec. 6, 2002, which claims priority fromU.S. Provisional Application No. 60/206,494, filed May 23, 2000, andfrom U.S. Provisional Application No. 60/206,276, filed May 23, 2000,which applications and publication are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] Semipermeable membranes play an important part in industrialprocessing technology and other commercial and consumer applications.Examples of their applications include, among others, biosensors,transport membranes, drug delivery systems, water purification devices,supported catalysts, including supported enzyme catalysts, and selectiveseparation systems for aqueous and organic liquids carrying dissolved orsuspended components.

[0003] Generally, semipermeable membranes operate as separation devicesby allowing certain components of a liquid solution or dispersion ofsolvent and one or more solutes to permeate through the membrane whileretaining other components in the solution or dispersion. The componentsthat permeate or are transmitted through the membrane are usually termedpermeate. These components may include the solution or dispersionsolvent alone or in combination with one or more of the solution ordispersion solutes. The components retained by the membrane are usuallytermed retentate. These components may include either or both of thesolution or dispersion solvent and one or more of the solution ordispersion solutes. Either or both of the permeate and retentate mayprovide desired product.

[0004] The industry has, for convenience, categorized thesesemipermeable membranes as microfiltration, ultrafiltration,nanofiltration or reverse osmosis membranes. These categories do nothave rigid definitions. Most definitions available in the industryarrange the membranes according to properties and function. For example,the microfiltration and ultrafiltration membranes are often defined bytheir pore sizes. Typically, these membranes contain recognizable poresof sizes from 0.1 to 10 microns and 1 nm to 0.1 micron respectively.Nanofiltration (NF) and reverse osmosis (RO) membranes, in contrast, aremost often regarded as not containing recognizable pores. Instead, NFand RO membranes are believed to transmit liquid permeate through voidspaces in the molecular arrangement of the material making the membranebarrier layer. NF membranes typically are used, for example, tofractionate monovalent ions from divalent ions or to fractionate smallorganic compounds from other small organic compounds (monosaccharidesfrom disaccharides, for example) or salts from organic compounds. ROmembranes generally retain all components other than the permeatingliquids such as water, with certain exceptions such as weakly ionizingHF, which tends to permeate with water through RO membranes. Undercertain circumstances, the RO membranes can also be used to separateand/or fractionate small organic molecules.

[0005] RO membranes are often found in industrial applications callingfor concentration of mixtures of inorganic salts, or concentration ofmixtures of small, very similar organic molecules. RO membranes are usedforemost for desalination either of municipal or well water or ofseawater. These membranes are also typically used in recovery operationssuch as mining, spent liquor recovery from industrial processing andgeneral industrial applications. The RO membranes function by retainingthe solution solute, such as dissolved salts or molecules, and allowingthe solution solvent, such as water, to permeate through the membrane.Commercial RO systems typically retain greater than 99% of most ionsdissolved in a solvent such as water.

[0006] In contrast, NF membranes are often found in industrialapplications calling for separation of one small compound from another.For example, NF membranes are used foremost for separation of alkalinesalts from alkaline earth salts such as separation of mixtures of sodiumand magnesium chlorides. Some NF membranes function by retaining thedouble charged ions while allowing the singly charged ions (with theircorresponding anions) to permeate with the solvent.

[0007] RO and NF membranes are typically characterized by twoparameters: permeate flux and retention ability. The flux parameterindicates the rate of permeate flow per unit area of membrane. Theretention ability indicates the ability of the membrane to retain apercentage of a certain component dissolved in the solvent whiletransmitting the remainder of that component with the solvent. Theretention ability is usually determined according to a standardretention condition.

[0008] RO and NF membranes are typically operated with an appropriatepressure gradient in order to perform the desired separations. Whenfunctioning to separate, the filtration process using a RO or NFmembrane overcomes the osmotic pressure resulting from the differentialconcentration of salts on the opposing sides of the membrane. Under anunpressurized situation osmotic pressure would cause solvent on the sidewith the lower salt concentration to permeate to the side having thehigher salt concentration. Hence, pressure must be applied to thesolution being separated in order to overcome this osmotic pressure, andto cause a reasonable flux of solvent permeate. RO membranes typicallyexhibit satisfactory flow rates, or fluxes, at reasonable pressures.Currently, typical commercial RO systems have fluxes on the order of 15to 50 lmh (liters per m² per hour) at about 7 to 30 atmospherespressure, depending on the application. Home RO systems typically run atlower pressures (1-6 atmospheres depending on line pressure) and lowerfluxes (5 to 35 lmh). Seawater desalination typically runs at higherpressures (40 atm to 80 atm) and fluxes in the range of 10 lmh to 30lmh. RO membranes also have advantageous salt retention characteristics.For example, to purify seawater, an RO membrane will typically have asalt retention value of at least 98.5 percent and preferably 99 percentor more, such that the total ion retention ability for commercial ROtreatment of seawater typically will be in excess of 99.5%.

[0009] The majority of semipermeable membranes functioning as RO and NFmembranes are cellulose acetate and polycarboxamide (hereinafterpolyamide) membranes as well as sulfonated polysulfone and othermembranes for NF alone. Polyamide membranes often are constructed ascomposite membranes having the thin polyamide film formed as a coatingor layer on top of a supporting polysulfone microporous membrane.Typically, the RO or NF membrane is formed by interfacial polymerizationor by phase inversion deposition. For example, U.S. Pat. No. 3,744,642to Scala discloses an interfacial membrane process for preparation of anRO or NF membrane. Additional U.S. patents disclosing polyamide andpolysulfonamide membranes include U.S. Pat. Nos. 4,277,344; 4,761,234;4,765,897; 4,950,404; 4,983,291; 5,658,460; 5,627,217; and 5,693,227.

[0010] Several characteristics are described in these and other U.S.patents pertaining to semipermeable membranes as factors foradvantageous operation of RO and NF membranes. These characteristicsinclude high durability, resistance to compression, resistance todegradation by extremes of pH or temperature, resistance to microbialattack, and stability toward potentially corrosive or oxidativeconstituents in feed water such as chlorine. Although the polyamidemembranes typified by U.S. Pat. No. 4,277,344 are widely used,especially in desalination operations to purify water, these membranesare susceptible to corrosive attack, as well as low pH and temperaturedegradation. Furthermore, microbial fouling of the membrane can causeloss of flux and/or retention characteristics. Nevertheless, currentpolyamide membranes substantially reach the goals of minimal thicknessand substantial freedom from flaws or imperfections, allowing forwidespread commercial use.

[0011] These two goals of minimal thickness and freedom from flaws,however, are not altogether compatible. As the thickness of thepolymeric film or membrane decreases, the probability of defect holes orvoid spaces in the film structure increases significantly. The defectholes or void spaces result in significant loss of solute retention.

[0012] Polysulfonamide membranes provide several possible advantagesover polyamide membranes. Although polysulfonamide membranes have beenreported, they have no appreciable commercial application. Generallythey have poor flux rates and low solute retention capabilities. Forexample, B. J. Trushinski, J. M. Dickson, R. F. Childs, and B. E.McCarry have described investigations of polysulfonamide membranes andtheir modifications in the course of attempts to achieve higher flux andbetter retention abilities. Trushunski, Dickson, Childs, and McCarryreport these attempts in the Journal of Membrane Science 143, 181(1998); Journal of Applied Polymer Science, 48, 187 (1993); Journal ofApplied Polymer Science, 54, 1233 (1994); and Journal of Applied PolymerScience, 64, 2381 (1997). Trushunski, Dickson, Childs, and McCarryhowever, have been unable to achieve the functional properties of thepolyamide membranes using polysulfonamides. Those functional propertiesare believed to enable at least in part the achievement of the typicalperformance thresholds qualifying a membrane for practical use.

[0013] Therefore there is a need for polysulfonamide membranes thatdisplay flux and retention capabilities like those of the polyamidemembranes. In addition, there is a need to develop semipermeablemembranes such as RO and NF membranes that are stable to strong acidconditions and/or stable to oxidative conditions. There is a furtherneed to develop semipermeable membranes that will be useful in heavy,corrosive industrial applications including mineral mining, industrialdesalination, industrial waste purification, industrial and residentialrecycling and solute recovery.

SUMMARY OF THE INVENTION

[0014] These needs are met by the present invention, which provides asulfonamide polymer matrix, which, when configured as a semipermeablemembrane, exhibits improved flux, improved retention properties, and/orimproved stability. The invention also provides a process for preparinga sulfonamide polymer matrix of the invention.

[0015] More specifically, the present invention is directed to thefollowing developments:

[0016] 1. a sulfonamide polymer matrix;

[0017] 2. a membrane including such a matrix;

[0018] 3. a composite membrane including such a matrix;

[0019] 4. an article including a combination of the sulfonamide polymermatrix and a support material;

[0020] 5. a process for preparing the sulfonamide polymer matrix;

[0021] 6. a process for preparing a membrane or a composite membrane ofthe invention

[0022] 7. a polysulfonamide matrix, membrane, or composite membrane madeaccording to the process of the invention;

[0023] 8. a polysulfonamide matrix formed of a polymeric reactionproduct of a compound having at least two reactive sulfonyl groups andan amine compound having at least two reactive primary amine groups andat least one secondary or tertiary amine group;

[0024] 9. use of a polysulfonamide membrane of the invention to separatecomponents of a fluid mixture;

[0025] 10. a process for separation of such fluid mixtures;

[0026] 11. a polysulfonamide membrane that is stable under low pHconditions or corrosive or oxidative conditions;

[0027] 12. an apparatus or device including the matrix or the membrane;and

[0028] 13. use of the sulfonamide matrix as a coating.

[0029] The sulfonamide polymer matrix is composed of sulfonyl compoundresidues having at least two sulfonyl moieties and amine compoundresidues having at least two amine moieties wherein the sulfonyl andamine moieties form at least some sulfonamide groups (—SO₂—N(R)—).Preferably the amine compound residue having at least two amine moietiesis not polyethyleneimine having a molecular weight of greater than orequal to 600 daltons. More preferably, the amine compound residue havingat least two amine moieties is not polyethyleneimine having a molecularweight of greater than or equal to 500 daltons. Even more preferably,the amine compound residue having at least two amine moieties is notpolyethyleneimine having a molecular weight of greater than or equal to400 daltons.

[0030] The sulfonamide polymer contains at least some sulfonamidelinkages in the backbone of the polymer molecules(polymer-SO₂—N(R)-polymer). Other functional and/or nonfunctionallinkages (i.e. optional linkages) such as amide, ester, ether, amine,urethane, urea, sulfone, carbonate, and carbon-carbon sigma bondsderived from olefins may also optionally be present in the backbone. Thepreferable backbone linkages are sulfonamide linkages, optionally alsocontaining amide, amine, carbon-carbon, ether and/or sulfone linkages.Especially preferably, a sulfonamide linkage backbone with one or moreof the optional linkages is stable to low pH conditions. Also, theamount of optional linkages is preferably no more than about 50 percent,30 percent, or 10 percent, and more preferably, no more than about 5percent of the number of sulfonamide linkages present in the sulfonamidepolymer backbone.

[0031] Preferably, the sulfonamide matrix may be at least partiallycross-linked. Preferably, the cross-linking is achieved though inclusionof at least some of the sulfonyl compound residue and/or the aminecompound residue as residues having three or more groups. Preferably,the sulfonyl compound residues include some portion of compound with atleast three sulfonyl groups and/or amine groups so that polymer chainsare cross-linked. Preferably, the sulfonamide polymer of the matrix isan interfacial polymer. In further preferred embodiment of thesulfonamide matrix, the matrix is free of polymer derived from anaqueous latex of sulfonamide polymer. Additionally, the matrix ispreferably free of sulfonamide polymer derived from a polyalkylamine(e.g. polyethyleneamine). In another preferred embodiment, the inventionprovides a matrix wherein the polymer on one side of the matrix containsat least some sulfonic acid groups, and/or the polymer on the oppositeside or on one side of the matrix contains at least some amine groups.

[0032] The polymer matrix according to the invention is preferablyformed at least in part from compound residues derived from a sulfonylcompound having any organic nucleus and at least two activated sulfonylgroups. The sulfonyl compound may be a polymer, monomer, an oligomer, acomplex molecule or other organic moiety having at least two activatedsulfonyl groups. Preferably, this sulfonyl compound has Formula I:

X—SO₂—Z—(SO₂—X)_(n)  I

[0033] wherein Z may be any organic nucleus that does not react withactivated sulfonyl groups or with primary amine groups and X is anyleaving group appropriate for creation of activated sulfonyl groups. Anactivated sulfonyl group is a sulfonyl group that will react with aprimary or secondary amine group to produce a sulfonamide group.Preferably, Z is an organic nucleus of 1 to about 30 carbon atoms, whichoptionally may contain oxygen, sulfur and/or nitrogen atoms assubstituents or within the nucleus structure itself. The organic nucleuspreferably may be aliphatic (i.e., linear or branched alkyl or alkenylor alkynyl), cycloaliphatic, aryl, arylalkyl, heteroaliphatic,heterocycloaliphatic, heteroaryl or heteroarylalkyl wherein the heteronucleus contains one or more oxygens, sulfurs or nitrogens. The organicnucleus may be unsubstituted or substituted wherein the substituents arepolar, ionic or hydrophobic in nature. Such substituents may include butare not limited to halogen, nitrile, alkyl, alkoxy, amide, ester, ether,amine, urethane, urea, carbonate and/or thioether groups optionallysubstituted with aliphatic groups of 1 to 6 carbons. Such substituentsmay also include but are not limited to halogen, carboxylic acid,sulfonic acid, phosphoric acid, and/or aliphatic groups of 1 to 12carbons, the latter aliphatic groups optionally being substituted byhalogens. The term “n” may be an integer of from 1 to 3. X may behalogen, azide, a mixed sulfonoxy group (forming an activated sulfonylanhydride) or the like.

[0034] The polymer matrix of the invention preferably may also be formedfrom amine compound residues derived from an amine compound having anyorganic nucleus and at least two primary and/or secondary amine groups.The amine compound may be a polymer, monomer, an oligomer, a complexmolecule or any organic moiety having at least two primary and/orsecondary amine groups. Preferably, the amine compound has Formula II:

R¹—NH—Y—[(CH₂)_(j)(NH—R²)]_(m)  II

[0035] wherein R¹ and R² are independently hydrogen or aliphatic groupsof 1 to 30 carbons, Y is any appropriate organic nucleus, preferably of1 to 30 carbons, and optionally containing one or more oxygen, sulfur ornitrogen atoms. Preferably, Y is an aliphatic, aryl or arylalkyl groupof 1 to 30 carbons or is a corresponding heteroaliphatic, heteroaryl orheteroarylalkyl group containing 1 or more oxygen, sulfur or nitrogenatom. The letter m is an integer from 1 to 3 and j is zero or an integerof from 1 to about 10.

[0036] An especially preferred sulfonamide polymer matrix of theinvention is formed from one or more combinations of the followingcompound residues: naphthalene disulfonyl residues of any substitutionpattern, naphthalene trisulfonyl residues of any substitution pattern,benzene disulfonyl residues of any substitution pattern, benzenetrisulfonyl residues of any substitution pattern, pyridine disulfonylresidues of any substitution pattern, alpha, omega diaminoalkanes of 1to 10 carbons, ethylene diamine, triethylenetetramine, tetraethylenepentamine, tris(2-aminoethyl)methane and tris-(2-aminoethyl)amine,meta-xylene diamine, 2-hydroxy-1,3-diaminopropane. As a seconddevelopment, the invention includes a polysulfonamide membrane. Theinvention also includes a composite membrane including a sulfonamidepolymer matrix of the invention located on at least one side of a porousor microporous support material. The porous support material may becomposed of any suitable porous material including but not limitedpaper, modified cellulose, interwoven glass fibers, porous or wovensheets of polymeric fibers and other porous support materials made ofpolysulfone, polyethersulfone, polyacrylonitrile, cellulose ester,polyolefin, polyester, polyurethane, polyamide, polycarbonate,polyether, and polyarylether ketones including such examples aspolypropylene, polybenzene sulfone, polyvinylchloride, andpolyvinylidenefluoride. Ceramics, including ceramic membranes, glass andmetals in porous configurations are also included. The support materialtypically contains pores have sizes ranging from about 0.001 microns toabout 1 micron. The composite membrane may be formed as sheets, hollowtubes, thin films, or flat or spiral membrane filtration devices. Thesupport thickness dimension ranges from about 1 micron to approximately500 microns (preferably, about 1 micron to approximately 250 microns),with the upper boundary being defined by practical limitations.

[0037] The polysulfonamide membrane of the invention has an independentA value and independent retention value that enables it to operate in apractical setting. Its A value and retention value bring the compositemembrane within the ranges achieved by polyamide membranes. Either as anRO or an NF membrane, the polysulfonamide composite membrane of thepresent invention preferably has an water permeability A value of atleast 2 or 3 when the A value is the sole parameter being used todescribe the membrane. When used as an RO membrane, the polysulfonamidecomposite membrane of the present invention preferably has an NaClretention value of at least 98 percent when the retention value is thesole parameter being used to describe the membrane. In combinations of Avalue and retention value, the polysulfonamide composite membrane of thepresent invention has an A value from at least about 1 to at least about20 and a corresponding NaCl retention of at least about 99 percent downto about 10 percent.

[0038] When used as an NF membrane to retain magnesium sulfate and passsodium chloride, the retention values regarding separate magnesiumsulfate and sodium chloride salts challenges ranges from at least about90 to at least about 95 percent retention of magnesium sulfate with atleast 50 to at least about 75 percent transmission of sodium chloride.For separate magnesium sulfate and magnesium chloride tests, theretention/transmission values are at least about 90 to at least about 95percent and at least about 30 to at least about 60 percent respectively.For separate sodium sulfate and magnesium chloride tests, theretention/transmission values range from at least about 90 to at leastabout 95 percent and at least about 30 percent to at least about 60percent respectively. For separate sodium sulfate, sodium chloridetests, the retention/transmission values are at least about 90 to atleast about 95 percent and at least about 50 to at least about 75percent respectively.

[0039] As a third development, the invention includes a combination ofthe matrix layered or coated upon the surface of any substrate includingbut not limited to a porous bead, a chromatographic material, metalsurfaces, a microdevice, a medical device, a catheter, a CD coating, asemiconductor wafer, digital imaging printing media, a photoresist layerand the like.

[0040] As a fourth development, the invention includes a process forpreparing the sulfonamide polymer matrix. The process includes the stepof contacting a first phase including an amine compound having at leasttwo amine groups which are capable of forming sulfonamide bonds, with asecond phase including a sulfonyl compound having at least two sulfonylgroups which are capable of forming sulfonamide bonds.

[0041] The first and second phases may be miscible or immiscible in eachother. If miscible, the two phases may mix at least to some extent, andpreferably to a significant extent upon contact. If immiscible, the twophases may mix at least to some extent or may not mix at all. Preferablythese phases are at least substantially immiscible in each other, andespecially preferably nearly completely immiscible in each other.

[0042] The first and second phases may be neat starting materials orthey may include one or more solvents.

[0043] The time for formation of the matrix resulting from contact ofthe phases is sufficient to generate the matrix as a barrier to furthersulfonamide production and is also typically short. As explained abovethe rapidity with which the matrix is formed bears upon its thickness,density and defect parameters. Preferably the time for matrix formationranges up to about 800 seconds or up to about 480 seconds, or morepreferably up to about 240 seconds or about 120 seconds. The rate ofreaction between the sulfonyl compound and the amine compound may bepromoted through the use of a catalyst, heat, and/or other reactionacceleration technique. Preferably, the first or second phase includes acatalyst for promotion of sulfonamide bond formation. Preferably, thecatalyst is a Lewis base nucleophile such as a nitrogen, phosphorusinorganic or organic compound.

[0044] As a fifth development, the invention includes thepolysulfonamide membrane or composite membrane prepared according to aprocess of the invention.

[0045] As a sixth development, the invention includes certain polymericformulas for the sulfonamide polymer matrix. These formulas involve thepolymeric reaction product of an aromatic or aliphatic compound havingat least two active sulfonyl groups and amine compound having at leasttwo active primary groups and also at least one secondary or tertiaryamine group positioned between the two primary amine groups. Thesemipermeable membrane embodiment of this development is especiallyuseful under harsh acidic conditions (pH≦3).

[0046] As a seventh development, the invention involves the use of theforegoing membranes for separation of a fluid mixture into its permeateand retentate. The fluid mixture may contain a mixture of inorganicsalts, similar small organic molecules, a low pH and/or corrosive oroxidative substances. The separated permeate may be water or purifiedorganic liquid. The retentate preferably will contain the solute.

[0047] As an eighth development, the invention includes a process forseparation of a fluid mixture. This process uses the polysulfonamidemembrane of the invention to separate the fluid mixture into a permeateand a retentate.

[0048] As a ninth development, the invention includes the performance ofthe polysulfonamide membrane of the invention under harsh conditionssuch as but not limited to extreme pH, temperature, and/or oxidativeconditions. The NF polysulfonamide membrane of the invention is capableof performing significant separation of alkaline, alkaline earth, andtransition metal ions as salts from feed solutions that are acidicand/or contain corrosive materials. The NF polysulfonamide membrane ofthe invention is capable of retaining certain metal ions as inorganicsalts while allowing the neutral, acidic, or basic aqueous medium topermeate. Additionally, the membranes of the invention are capable ofseparating components and/or separating solvent from dissolved solidscomponents of such feed solutions as may come from the mineralseparation industry, the paints and coatings industry, the food andcosmetics industry, the metals and fabrication industry, and theplastics industry as well as others. Preferably the polysulfonamidemembranes of the invention will continue to perform significantseparation from a feed solution even though the feed solution containsstrong acids such as sulfuric acid, nitric acid, hydrochloric acid andthe like.

[0049] As a tenth development, the invention includes an apparatus ordevice for separation of solutes from a feed solution. The apparatus ordevice includes a polysulfonamide matrix of the invention (e.g. amembrane or a composite membrane).

[0050] As an eleventh development, the invention includes the use of thematrix as an adhesive promoter, a surface lubricant, a chemicallyresistant coating, or a photoresist.

[0051] As a twelveth development, it has been discovered that asulfonamide polymer matrix comprising 1,3,5-benzenetrisulfonyl residuesand alkyldiamine residues wherein some of the 1,3,5-benzenetrisulfonylresidues and alkyldiamine residues form sulfonamide groups in thepolymer backbone, possesses an unexpected and advantageously high levelof stability toward oxidative conditions. Accordingly, one preferredaspect of the invention provides a sulfonamide polymer matrix comprising1,3,5-benzenetrisulfonyl residues and alkyldiamine residues, whereinsome of the 1,3,5-benzenetrisulfonyl residues and alkyldiamine residuesform sulfonamide groups in the polymer backbone. The alkyldiamine canpreferably be a compound of formula II: R¹—NH—Y—[(CH₂)_(j)(NH—R²)]_(m);wherein Y is C₁-C₁₈alkyl; each R¹ and R² is hydrogen; m is 1; and j iszero. Preferably, Y is C₁-C₁₀alkyl; and more preferably, Y isC₁-C₁₆alkyl. Most preferably, the alkyldiamine is ethanediamine.

Definitions

[0052] Unless otherwise stated, the following definitions apply.

[0053] The term “matrix” means a regular, irregular and/or randomarrangement of polymer molecules. The molecules may or may not becross-linked. On a scale such as would be obtained from SEM, x-ray orFTNMR, the molecular arrangement may show a physical configuration inthree dimensions like those of networks, meshes, arrays, frameworks,scaffoldings, three dimensional nets or three dimensional entanglementsof molecules. The matrix is usually non-self supporting and most oftenis constructed as a coating or layer on a support material. Thesulfonamide polymer matrix has an average thickness from about 5 nm toabout 600 nm, preferably about 5 to about 400 nm. In usual practice, thematrix is grossly configured as an ultrathin film or sheet. Morepreferably, the matrix has an average thickness from about 5 nm to about100 nm, or from about 15 nm to about 100 nm, or from about 25 nm toabout 90 nm.

[0054] The term “membrane” means a semipermeable matrix.

[0055] The term “composite membrane” means a composite of a matrixlayered or coated on at least one side of a porous support material.

[0056] The term “support material” means any substrate onto which thematrix can be applied. The substrate may be porous or non-porous.Included are semipermeable membranes especially of the micro- andultrafiltration kind, metal, ceramic, fabric, plastic, wood, masonry,building materials, electronic components, medical components,filtration materials as well as others.

[0057] The term “stable,” when used to characterize a membrane in acid,means that substantially all of the membrane remains intact afterexposure to a solution of about 20% sulfuric acid for one day at 90° C.or 30 days at 40° C., preferably very substantially all of the membraneremains intact under these conditions and especially preferablyessentially all of the membrane remains intact under these conditions.In this context of acid treatment, the terms “substantially all, verysubstantially all and essentially all” mean respectively that themembrane maintains at least 90%, at least 95%, at least 99% of itssulfur-nitrogen sulfonamide bonds after it has been exposed to theseconditions. Also, maintaining at least substantially all of thesulfur-nitrogen sulfonamide bonds in certain membrane situationsincludes an improvement of the original permeation and retention valuesof the membrane such that the after-test permeation and retention valuesmay be better than the original values.

[0058] The term “polyamide” means a polymer having a backbone ofrepeating carboxamide groups all of the same arrangement (—CONH—) or ofalternating reverse arrangement (—CONH—R—NHCO—). The term does notinclude polymers having sulfonamide groups in the backbone(polymer-SO₂—N-polymer).

[0059] The term “20% sulfuric acid” means a solution of deionized waterand 20% sulfuric acid by weight.

[0060] The term “average thickness” is the average matrixcross-sectional dimension. It means the average distance in crosssection from one side of the matrix to the opposite side of the matrix.Since the matrix has surfaces that are at least some extent uniform, theaverage thickness is the average distance obtained by measuring thecross-sectional distance between the matrix sides. Techniques such asion beam analysis, X-ray photoelectron spectroscopy (XPS), and scanningelectron microscopy (SEM) can be used to measure this dimension. Becausethe cross-sectional dimension usually is not precisely the same at allpoints of the matrix, an average is typically used as an appropriatemeasurement. The preferred technique for measuring this dimension isSEM.

[0061] The term “permeation” means transmission of a material through amembrane.

[0062] The term “A value” in the context of the present inventionrepresents the water permeability of a membrane and is represented bythe cubic centimeters of permeate water over the square centimeters ofmembrane area times the seconds at the pressure measured in atmospheres.An A value of 1 is essentially 10⁻⁵ cm³ of permeate over themultiplicand of 1 centimeter squared of membrane area times 1 second ofperformance at a net driving pressure of one atmosphere. In the contextof the present invention, A values given herein have the following unitdesignation: 10⁻⁵ cm³/(cm².sec.atm.) or 10⁻⁵ cm/(sec.atm) at 25° C.

A=permeate volume/(membrane area*time*net driving pressure).

[0063] The term “recovery value” means the ratio of permeate fluid flowto feed fluid flow, expressed as a percentage. It should be noted thatunder most circumstances the flux is directly related to the appliedtrans-membrane pressure, i.e., a membrane can provide a specific flux ofpermeate at a given pressure. This flux is often given in units of lmh.

[0064] The term “net driving pressure” is equal to the averagetrans-membrane pressure minus the feed-permeate osmotic pressuredifference.

[0065] The term “transmission value” means the solute concentration inthe permeate divided by the average of the solute concentration in thefeed and in the concentrate, expressed as a percentage [i.e.transmission value=permeate/((feed+concentrate)/2), expressed as apercentage]. The concentrate is the fluid that flows completely past,but not through, the membrane. The term “retention value” means, in thecontext of the present invention, 100% minus the transmission value. Theterm “passage” or “% Pass” is equivalent to the transmission value.Unless otherwise stated, the retention and transmission values areachieved by passing a 1800 to 2200 ppm solution of the specified solutein DI water at a pH of 6.5 to 7.5, at 24-26 degrees C, at 221-229 psitransmembrane pressure, at a recovery value of less than 2%, at aRenyolds number of at least 2000 across the membrane, and by collectingpermeate samples for permeation analysis between the first and secondhour of testing. The term “recovery value” means, in the context of thepresent invention, the ratio of permeate fluid flow to feed fluid flow,expressed as a percentage.

[0066] The term “aliphatic” or “aliphatic group” is known in the art andincludes branched or unbranched carbon chains which are fully saturatedor which comprise one or more (e.g. 1, 2, 3, or 4) double or triplebonds in the chain. Typically, the chains comprise from 1 to about 30carbon atoms. Preferably, the chains comprise from 1 to about 20 carbonatoms, and more preferably, from 1 to about 10 carbon atoms.Representative examples include methyl, ethyl, propyl, isopropyl,pentyl, hexyl, propenyl, butenyl, pentenyl, propynyl, butynyl, pentynyl,hexadienyl, and the like.

[0067] The term “cycloaliphatic” or “cycloaliphatic group” is known inthe art and includes mono-cyclic and poly-cyclic hydrocarbons which arefully saturated or which comprise one or more (e.g. 1, 2, 3, or 4)double or triple bonds in the ring(s). Such groups comprise from 1 toabout 30 carbon atoms. Preferably, from 1 to about 20 carbon atoms, andmore preferably, from 1 to about 10 carbon atoms. Representativeexamples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,cyclopentenyl, cyclohexenyl, and the like.

[0068] The term “aryl” denotes a phenyl radical or an ortho-fusedbicyclic carbocyclic radical having about nine to ten ring atoms inwhich at least one ring is aromatic. Representative examples includephenyl, indenyl, naphthyl, and the like.

[0069] The term “heteroaryl” denotes a group attached via a ring carbonof a monocyclic aromatic ring containing five or six ring atomsconsisting of carbon and one to four heteroatoms each selected from thegroup consisting of non-peroxide oxygen, sulfur, and N(X) wherein X isabsent or is H, 0, (C₁-C₄)alkyl, phenyl or benzyl, as well as a radicalof an ortho-fused bicyclic heterocycle of about eight to ten ring atomsderived therefrom, particularly a benz-derivative or one derived byfusing a propylene, trimethylene, or tetramethylene diradical thereto.Representative examples include furyl, imidazolyl, triazolyl, triazinyl,oxazoyl, isoxazoyl, thiazolyl, isothiazoyl, pyrazolyl, pyrrolyl,pyrazinyl, tetrazolyl, pyridyl, (or its N-oxide), thienyl, pyrimidinyl(or its N-oxide), indolyl, isoquinolyl (or its N-oxide) quinolyl (or itsN-oxide), and the like.

[0070] The term “heteroaliphatic” or “heteroaliphatic group” is known inthe art and includes branched or unbranched carbon chains wherein thechain is interrupted with one or more (e.g. 1, 2, 3, or 4 ) non-peroxyoxygen, sulfur or nitrogen atoms. Typically, the chains comprise from 1to about 30 carbon atoms and from about 1 to about 10 heteroatoms.Preferably, the chains comprise from 1 to about 20 carbon atoms and fromabout 1 to about 10 heteroatoms; and more preferably, from 1 to about 10carbon atoms and from about 1 to about 5 heteroatoms. Representativeexamples include 2-methoxyethyl, 3-methoxypropyl, and the like.

[0071] The term “heterocycloaliphatic” or “heterocyclicaliphatic group”is known in the art and includes mono-cyclic and poly-cyclicheterocycles which are fully saturated or which comprise one or more(e.g. 1, 2, 3, or 4) double bonds in the ring, and which comprise one ormore (e.g. 1, 2, 3, or 4) non-peroxy oxygen, sulfur or nitrogen atoms inone or more ring. Typically, the rings comprise from 1 to about 30carbon atoms and from about 1 to about 10 heteroatoms. Preferably, thechains comprise from 1 to about 20 carbon atoms and from about 1 toabout 10 heteroatoms; and more preferably, from 1 to about 10 carbonatoms and from about 1 to about 5 heteroatoms. Representative examplesinclude tetrahydrofuranyl, tetrahydrothiophenyl, pyrrolidinyl,piperidinyl, morpholinyl, and dihydropyranyl, and thiomorpholinyl, andthe like.

DETAILED DESCRIPTION OF THE INVENTION

[0072] The present invention represents a significant advance in thedevelopment of membrane technology overall and specifically in the fieldof polysulfonamide membranes. Typical, known polysulfonamide membraneshave low water flux and sodium chloride retention capabilities. They areunable to perform in a manner comparable to that of commercial polyamideRO and NF membranes. The membranes of the present invention, however,present improved performance and durability properties.

[0073] The sulfonamide polymer matrix of the present invention can havea number of differing functions depending upon its composition, itspreparation process and the support material with which it is combined.Such combinations may act as semipermeable membranes, lubricants,bioactive materials, binding membranes, drug reservoirs, photoresists,catheters, chromatographic materials, semiconductor wafers as well asothers. In the combination as a semipermeable membrane, the matrix mayprovide properties of nanofiltration and reverse osmosis depending uponthe design of the matrix. Additionally, the polymer moleculesconstituting the matrix may be formed into microporous or ultraporouscoatings that may function as microfiltration or ultrafiltrationmembranes. Such coatings may be combined with appropriate supportmaterials or may simply be a skin on a core of the same molecularconfiguration (i.e. an asymmetric membrane).

[0074] Preferably, the sulfonamide polymer matrix in combination with asupport material according to the invention performs as a semipermeablecomposite membrane. Because of its extremely thin character, the polymermatrix of the present invention is most often formed as a composite on aporous or microporous support material when it is used in one of itspreferred forms for nanofiltration or reverse osmosis. The compositemembrane of the invention has a high flux and a high ability to rejectinorganic salts compared to known sulfonamide materials. Additionally,the composite membrane of the invention can function under harshconditions such as strong acid (e.g. pH≦about 3, 2, or 1 ) and highlycorrosive conditions.

[0075] The sulfonamide polymer matrix of the invention has an averagethickness ranging from about 5 nm to about 600 nm, preferably from about5 nm to about 400 nm. More preferably, the polymer matrix has an averagethickness of from about 10 to about 200 nm, especially more preferablyfrom about 10 to about 150 nm, most preferably about 15 to about 100 nm,and especially most preferably about 15-20 nm to about 70-90 nm.

[0076] In another preferred embodiment, the sulfonamide polymer matrixof the invention has an average thickness ranging from about 5 nm toabout 100 nm, preferably from about 15 nm to about 100 nm; and, morepreferably, from about 25 nm to about 90 nm.

[0077] The sulfonamide polymer matrix of the invention preferably has adensity that enables high permeation and flux yet enables significantretention when the matrix is configured as a semipermeable membrane. Thematrix of the invention may have a density of from about 0.25 g/cc toabout 4.0 g/cc, preferably from about 0.3 g/cc to about 3 g/cc, morepreferably from about 0.5 to about 2.0 g/cc, especially more preferablyabout 0.7 g/cc to about 1.7 g/cc, most preferably a density of fromabout 0.8 to about 1.6 g/cc. The mass to area ratio of the polymermatrix to the final membrane area may be from about 10 to 400 mg. permeter squared, preferably from about 20 to about 200 mg. per metersquared, more preferably from about 50 to about 150 mg per meter squaredor from more preferably from about 30 to about 150 mg per meter squared,most preferably from about 40 to about 100 mg per meter squared.

[0078] The sulfonamide polymer matrix of the invention is typically hasdefects of no more than about 10 percent of its volume, preferably nomore than 5 percent, especially preferably no more than 2 percent andmost especially no more than about 1 percent. In particular, a preferredmatrix according to the invention is preferably substantially free, morepreferably very substantially free, and most preferably essentially freeof defects.

[0079] The sulfonamide polymer is the reaction product of one or moresulfonyl compounds having at least two active sulfonyl groups and one ormore amine compounds having at least two active amine groups. Thesulfonyl and amine compounds may be monomers, polymers, oligomers,building blocks, condensation molecules, reactive units, complexmolecules or other organic moieties having the active sulfonyl groups oramine groups respectively. These descriptions have overlappingdefinitions which may be determined from general organic chemistry textssuch as “Organic Chemistry” 6^(th) or 7^(th) by R. Morrison and R. Boyd,Allyn & Bacon Pub.; or “Advanced Organic Chemistry”, 4^(th) Ed. by J.March, Wiley Interscience, as well as in “Hawley's Condensed ChemicalDictionary”, 11^(th) Ed., Sax and Lewis, Van Nostrand. For example, theoligomers may be repeating units linked by condensation groups or othergroups that will link together including but not limited to ether, amineand other groups discussed above.

[0080] In particular, the sulfonyl compound and amine compound may bebased upon any unsubstituted or substituted organic nucleus. The organicnucleus may optionally contain heteroatoms and preferably contains 1 toabout 30 carbon atoms. Preferably, the sulfonamide polymer matrix may beat least partially cross-linked. Preferably, the cross-linking isachieved though the use of at least some sulfonyl compound and/or aminecompound with three or more active sulfonyl or amine groupsrespectively. Cross-linking may also be provided by small molecules thatwill react with amine or sulfonic acid groups. Such small moleculesinclude but are not limited to polyisocyanates, polyepoxides, activatedpolyesters and the like.

[0081] Although it is not intended to be a limitation of the invention,it is believed that when it is configured as a semipermeable membrane,the sulfonamide matrix of the invention exhibits superior flux andretention properties as a result of its ultra thin character, itsdensity or mass per unit area, and its substantial freedom from defects.It is believed that rapid formation of the matrix, as well as theapplication of heat during the matrix formation, contributes to thedevelopment of these properties. It is also believed that a low degreeof roughness provides lower membrane fouling propensity.

[0082] As explained below, one process for the preparation of thesulfonamide polymer matrix involves an interfacial polymerization of thecompounds. A rapid interfacial polymerization of the compounds isbelieved to contribute to the formation of the sulfonamide polymermatrix having the foregoing desirable attributes. A theory about themechanism of interfacial polymerization is that one or more minivolumesof reaction media or reaction zones are believed to exist adjacent tothe two-phase interface of the reaction media and are believed to be thelocation(s) in which the polymerization reaction takes place. As thereaction proceeds, a matrix forms and diffusion of further compound intothe reaction zone or zones is believed to become limited by the newlyformed polymer matrix. It is believed that if the reaction between thetwo compounds in this reaction zone occurs at a rapid rate the zone orzones will be small, and the resulting matrix will be thin and dense. Itis believed that if the compound reaction is slow, matrix formation isslow and a greater portion of unreacted compound is able to diffuse fromone phase into a significant volume of the opposite phase with theresult of a larger reaction zone or zones. A thicker polymer matrixhaving a higher degree of void spaces or defects is believed to be theresult of such larger reaction zones. Moreover, it is believed that if adefect forms in the matrix, for example, as a result of void spaceformation, or a disturbance of the matrix, compound is believed to beable to diffuse through the defect and react to fill it. If the reactionis slow, the compound may be able to diffuse out of the defect and intoa significant portion of the opposite phase, leading to a large reactionzone and correspondingly thicker matrix.

[0083] A rapid rate of compound reaction relative to the unreactedcompound diffusion rate is believed to produce small reaction zones.Moreover, a polymeric barrier preventing further compound contact andreaction is believed to rapidly develop in the small zone construct. Itis believed that achievement of such a barrier to compound diffusionwithin a time ranging up to about 800 seconds (preferably about 480seconds) is sufficient to produce the ultra thin, highly dense matrixaccording to the invention. It is believed that this time-barrierinteraction provides for the high flux and high retention capability ofthe resulting polymer matrix. While this theory of matrix production canexplain the character of the matrix, other theories are also capable ofsimilar explanation.

[0084] Notwithstanding these theories for matrix production, it has beenfound that promotion of a rapid reaction rate between the sulfonylcompound and the amine compound in an interfacial process provides anultra thin, dense polymer matrix according to the invention. Generally,the interfacial technique is known in the art such as for preparation ofnylon materials and for membrane preparation as is described in U.S.Pat. No's. 4,277,344; 4,761,234; 4,765,897; 4,950,404; 4,983,291;5,658,460; 5,627,217; and 5,693,227. A typical interfacial process forthe slow formation of the polysulfonamide composite membrane follows theprocesses described in U.S. Pat. No's. 3,744,642 and 5,693,227. Theseprocesses are altered according to the present invention to achievepreparation of the sulfonamide matrix of the invention.

[0085] According to the process of the invention, a first phasecontaining a sulfonyl compound having at least two active sulfonylgroups is reactively contacted with a second phase containing an aminecompound having at least two active amine groups. The time during whichthe reactive contact takes place is the time needed for formation ofmatrix. This duration ranges up to about 900 seconds, preferably up toabout 600 seconds, more preferably up to about 480 seconds, 240 secondsor 120 seconds, most preferably up to about 60 seconds.

[0086] One aspect of the invention provides a process for preparing asulfonamide polymer matrix comprising: contacting a first phasecomprising an amine compound having an organic nucleus and at least twoprimary and/or secondary amine groups, with a second phase comprising asulfonyl compound having an organic nucleus and at least two sulfonylgroups capable of forming sulfonamide bonds with an amine group to formthe matrix of sulfonamide polymer, wherein the time for formation thematrix is less than 900 seconds. It is to be understood that a smallamount of residual amine and sulfonyl reactive groups may remain andreact after this time period, without departing from the scope of theinvention.

[0087] The first and second phases may be miscible or immiscible. Asused herein, miscible means capable of forming a single phase, andimmiscible means incapable of forming a single phase.

[0088] The first and second phases may be neat starting materials orthey may include one or more solvents. The phases may mix at least tosome extent or not mix. Although neat amine compound and neat sulfonylcompound can be used as the first and second phases if they are liquids,a typical process involves dilution of the amine compound and sulfonylcompound with first and second solvents that preferably are immiscible.

[0089] They also may preferably provide at least a degree, howeverminor, of solubility to both the sulfonyl compound and the aminecompound. Preferably, a solvent is inert toward the reactant and thesupport material. Preferably, the solvent for the amine compound iswater or an alkyl, aryl or arylalkyl alcohol or polyol. Preferably, whenthe solvent for the sulfonyl compound is an organic solvent, the organicsolvent may be chosen to have a density less than that of the solventfor the second phase. Although in some processing situations of theinvention, the organic solvent may have a density greater than that ofthe solvent for the second phase.

[0090] Preferably, the solvent for the sulfonyl compound is an organicsolvent that is substantially immiscible in water or the alcohol solventused for the amine compound. The organic solvent/hydroxylic solventorder can also be reversed so that the sulfonyl compound is placed inwater or alcohol. This reversed solvent process is useful under somecircumstances.

[0091] If the reaction rate between the compounds is not sufficient toenable matrix formation according to the reaction duration given above,the reaction between compounds may be promoted by any suitabletechnique. Such techniques typically will positively influence the rateof reaction between the compounds. Catalysts may be used. Increasedtemperature may be used. A solvent that promotes the nucleophiliccharacter of the amine may be used. Solvents that stabilize polarreaction intermediates or reaction transition states may be used. Highlymobile leaving groups on the sulfonyl moiety of the sulfonyl compoundmay be used. The reactant concentrations in the interface reaction zonemay be promoted.

[0092] Typical rate promoters include the use of a catalyst such as aLewis base, a nucleophilic agent that is capable of interacting with anactive sulfonyl group. Phosphorus and nitrogen containing organiccompounds can function in this capacity. Examples include tertiaryamines and aromatic amines such as pyridine, and4-(N,N-dimethylamino)pyridine, 4-piperidinopyridine, imidazole andphosphines such as triphenyl phosphine. Further examples are given inU.S. Pat. No. 5,693,227.

[0093] The sulfonyl compound useful according to the process of theinvention to form the sulfonamide polymer matrix may be any sulfonylcompound as described above. The sulfonyl compound may be a sulfonicacid precursor, which is converted into the sulfonyl compound byformation of sulfonyl groups activated with leaving groups. The sulfonylcompound may contain least two activated sulfonyl groups and preferablymay be a mixture of di and tri activated sulfonyl group compounds. Thesulfonyl compound may also include at least in part a species with tetraand higher activated sulfonyl groups.

[0094] Preferably, the sulfonyl compound may be composed of any organicnucleus and preferably is a compound of Formula I.

X—SO₂—Z—(SO₂—X)_(n)  I

[0095] The Z and X groups of Formula I may be any as described above.Preferably, the Z group may be an organic nucleus of 1 to 30 carbons orany corresponding hetero nucleus including nitrogen or sulfur or oxygenwithin the hetero nucleus. The preferred Z nucleus has a multiple numberof sulfonyl group functional sites ranging from one to six or more.Additionally, the Z group may be substituted as described above.Preferably, these substituents may be halogen, ether, nitrile, alkyl,alkoxy, amine, amide, urethane, urea, carbonate, thioether and/or estergroups. Alkyl, alkenyl, cycloalkyl, alkylcycloalkyl, cycloalkenyl,alkylcycloalkenyl, aryl, arylalkyl, dialkylether, cycloalkyl and arylgroups and the corresponding groups containing nitrogen and sulfur, andeach having from 1 to 30 carbon atoms as is appropriate for the namedgroups are useful as preferred Z nuclei. Preferably, the Z nucleus isC₁-C₁₈ alkyl, C₂-C₁₈ alkenyl, C₃-C₇ cycloalkyl, C₄-C₁₆ alkylcycloalkyl,C₃-C₇ cycloalkenyl, C₄-C₁₆ alkylcycloalkenyl, C₆-C₁₄ aryl, C₆-C₁₀aryl-C₁-C₈ alkyl, or (C₆-C₁₀)aryl-C₁-C₈ alkyl-(C₆-C₁₀)aryl; with thesulfonyl valence (n of Formula I) being 1,2 or 3. More preferred Zgroups include C₁ to C₁₈ alkyl, C₆ to C₁₄ aryl, and C₁ to C₈ alkyl.Especially preferred Z groups include C₆ to C₁₄ aryl, such as phenyl,naphthyl or anthracenyl.

[0096] Leaving groups “X” which provide activated sulfonyl groupsinclude halogens, sulfonyl anhydrides, activated sulfonyl esters, andother known leaving groups. Examples include tosylates, brosylates,nosylates, mesylates, perchlorates, alkanesulfonate esters,fluorosulfonates, triflates and nanoflates, trislates and azides. Thedefinitions of these groups as well as techniques for their formationare given in J. March, Advanced Organic Chemistry, 4^(th) Ed.,Wiley-Interscience, New York 1992, which is incorporated in its entiretyherein by reference. Many of these leaving groups are themselvessulfonates so that a sulfonate anhydride is formed as the activesulfonyl group. Particularly preferred are the halides such as chloride,fluoride, bromide and iodide. These leaving groups constitute X ofpreferred Formula I above.

[0097] Preferred amine compounds useful according to the process of theinvention to form the sulfonamide polymer include those of Formula II.

R¹—NH—Y—[(CH₂)_(j)(NH—R²)]_(m)  II

[0098] In Formula II, Y may be any group as discussed above. Preferably,Y may be an organic nucleus of 1 to 30 carbon atoms and optionallyincluding oxygen, sulfur or nitrogen atoms. Included are alkyl, alkenyl,cycloalkyl, alkylcycloalkyl, cycloalkenyl, alkylcycloalkenyl, aryl,arylalkyl groups of C₁ to C₃₀ carbon atoms as is appropriate for thenamed groups with optional nitrogen, sulfur or/and oxygen atoms. The Rgroups of Formula II may preferably and independently be hydrogen,—N(R⁴)₂, C₁-C₈ alkoxy, C₁-C₁₈ alkyl, C₂-C₁₈ alkenyl, C₃-C₈cycloalkyl,C₃-C₈ cycloalkenyl, C₄-C₂₀ alkylcycloalkyl, C₄-C₂₀ alkylcycloalkenyl,C₆-C₁₀ aryl, or C₆-C₁₀ aryl-C₁-C₈ alkyl. The R⁴ groups are independentlyhydrogen, C₁-C₈ alkoxy, C₁-C₁₈ alkyl, C₂-C₁₈ alkenyl, C₃-C₈ cycloalkyl,C₃-C₈ cycloalkenyl, C₄-C₂₀ alkylcycloalkyl, C₄-C₂₀ alkylcycloalkenyl,C₆-C₁₀ aryl, or C₆-C₁₀ aryl-C₁-C₈ alkyl. Examples of Y with oxygen,nitrogen or sulfur atoms include ether units, secondary or tertiaryamine units and thioether units. Examples include oxydiethylenyl,azadiethylenyl, and thiodiethylenyl. Preferably, Y may be C₁-C₁₈ alkyl,C₂-C₁₈ alkenyl, C₃-C₇ cycloalkyl, C₄-C₁₆ alkylcycloalkyl, C₃-C₇cycloalkenyl, C₄-C₁₆ alkylcycloalkenyl, C₆-C₁₀ aryl, C₆-C₁₀ aryl-C₁-C₈alkyl (C₆-C₁₀)aryl-C₁-C₈ alkyl-(C₆-C₁₀)aryl or C₁-C₁₈-NHR³. The R³ groupmay be hydrogen, C₁-C₈ alkoxy, C₁-C₁₈ alkyl, C₂-C₁₈ alkenyl, C₃-C₈cycloalkyl, C₃-C₈cycloalkenyl, C₄-C₂₀ alkylcycloalkyl, C₄-C₂₀alkylcycloalkenyl, C₆-C₁₀ aryl, or C₆-C₁₀ aryl-C₁-C₈ alkyl.

[0099] Reaction temperature also can facilitate a higher rate ofreaction. Conduction the reaction at higher than ambient temperaturewill promote the reaction between the active sulfonyl groups and theactive amine groups, and will also facilitate the transfer of compoundfrom its parent phase to the interfacial reaction zone. The reactiontemperature is constrained by the boiling points of the solventspreferably being employed in the reaction although under certaincircumstances such as under higher than ambient pressure, thetemperature of reaction can exceed the normal boiling point of thesolvent. Preferably, the temperature of the reaction may range fromambient to 250° C. or more, more preferably from about 30° to about 200°C. Heat can conveniently be applied by heating one or both of thereaction phases, and/or by carrying out all or a portion of the matrixformation in an oven.

[0100] The solvents selected also have an effect upon the reaction rateand size of the reaction zone. For example, one solvent may be water orC₁ to C₃ alcohol or polyol while the other solvent may be any organicliquid. Alternatively, one solvent may be water and the other may be aC₂ to C₆ alcohol or mixture of alcohol and another organic solvent. Suchorganic liquids include C₅ to C₁₂ aliphatic hydrocarbons, aromatichydrocarbons such as benzene, substituted aromatic hydrocarbons such ashalobenzene, monoglyme, diglyme, polyethers, hydrocarbon mixtures,petroleum ether as well as fluorinated and fluorochlorocarbons such ascarbon tetrachloride, chloroperfluoroethane, the freons, and the like.Further examples of these organic liquids include C₂ to C₁₀ ethers, C₃to C₁₀ ketones and C₃ to C₁₂ aliphatic esters. Preferably, mixtures ofsuch organic liquids can also be employed to improve solvent properties.The two kinds of solvent can be miscible so long as the reaction isconducted in a fashion to produce the matrix as an ultra thin film. Suchoperations would include metering the first phase followed by rapidimmersion and removal of the second phase.

[0101] Partially miscible solvents can also be employed in somecircumstances to promote the reaction rate of the sulfonyl compound andthe amine compound. The partial miscibility may sometimes increase thediffusion rate of the compounds so that if their reaction is fast, theoverall rate of matrix formation can be promoted. Use of solvents suchas ethyl acetate or acetone and water to produce certain types ofsulfonamide polymer matrices can be of benefit when it is desired tohave polymeric chains with terminal sulfonic acid groups.

[0102] Furthermore, use of mixed organic solvents, which increase thetotal polarity of the organic solvent system, may be of benefit tofaster reaction rates. A more polar organic phase will tend to stabilizethe polar transition states of the sulfonamide reactants and alsostabilize any polar intermediates in the reaction. This stabilizationcan lead to faster reaction times. For example, glyme can be used tosolubilize a sulfonyl halide compound. Then, this solution may be placedinto an Isopar (e.g. Isopar G). Additives such as aromatics, esters,ethers, ketones and nitriles can also be combined with the organic phaseto facilitate dissolution of the sulfonyl compound and/or to facilitatethe polymerization reaction.

[0103] The concentrations of compounds in solvent range typically are ina range that will promote fast reaction but will under mostcircumstances avoid polymer agglomeration into gel particles and thelike although there are situations where formation of gel particles ofthe sulfonamide polymer may be useful for the preparation of thecomposite membrane of the invention. Usually, the compoundconcentrations in the two phases may differ to some extent. The compoundconcentrations for amine and sulfonyl compound may range from about 0.01percent to about 100 percent (i.e., neat) by weight relative to thetotal weight of the mixture, preferably, about 0.1 percent to about 50percent, more preferably about 0.5 percent to about 20 percent, mostpreferably about 0.5 percent to about 10 percent by weight. Typicalamine concentrations may be from about 0.75 weight percent to about 4weight percent, preferably about 1 to about 2 weight percent.

[0104] Typical sulfonyl compound concentrations can be from about 0.01percent to about 10 percent by weight relative to the total weight ofthe mixture, preferably, about 0.03 percent to about 3 percent, morepreferably about 0.05 percent to about 0.8 percent, most preferablyabout 0.05 percent to about 0.3 percent by weight.

[0105] Generally, any inert support material having pore sizes fromabout 0.001 to about 50 microns in diameter can be used. The supportmaterial may be interwoven glass fibers, metal fibers, polymeric fibers,porous or woven sheets of such fibers, paper or paper-like materials andmicroporous supports made of polysulfone, polyethersulfone,polyacrylonitrile, cellulose ester, polypropylene, polyvinylchloride,polyvinylidenefluoride and polyarylether ketones as well as anycombination thereof. Ceramics, including ceramic membranes, glass andmetals in porous configurations can also be used.

[0106] For composite membrane applications, the support materialpreferably has an A value greater than 10, more preferably greater than40, and even more preferably greater than 100. Additionally, the supportmaterial preferably has a molecular weight cut off (measured by the ASTMmethod at 90% dextran rejection) of less than 500,000, more preferablyless than 100,000, more preferably less than 30,000, and most preferablyless than 20,000. It may also be preferred to treat the porous supportmaterial with corona, e-beam, or other discharge technique to facilitatecoating techniques.

[0107] Further additives and adjunct materials may be included withinthe polymer matrix of the invention so long as they do not inhibit thetwo compounds from forming the sulfonamide polymer. These additives maybe plasticizers, ionicity enhancers, wetting agents such as surfactants,desorption agents, surface modifiers, smoothing agents, acid acceptors,flux enhancing agents, drying agents, antifoaming agents and defoamingagents. These additives and materials may be inert or functional towardpromotion of semipermeation of solutions by RO and NF membranes. In atypical process for preparation of a composite membrane of theinvention, a roll of selected support material is contacted with anaqueous solution of the amine compound such as ethylene diamine at anappropriate concentration such as about 1 to about 5, preferably about1.5 to about 3, more preferably about 2 percent by weight relative tothe total weight of reactants, and a catalyst such as pyridine,trimethyl amine, dimethylaminopyridine or triphenyl phosphine. After thesupport material is removed from the aqueous solution, excess aminesolution may be removed via an air knife.

[0108] The support material coated with aqueous amine and catalyst isthen passed through a solution bath containing the sulfonyl compoundsuch as 1,4-benzenedisulfonyl chloride in an organic liquid such aspetroleum ether, ligroin, diglyme/ higher hydrocarbon, an Isopar,naphtha solvent or a mixture of monoglyme and Isopar G. Theconcentration of sulfonyl compound is the organic liquid may range fromabout 0.1 to about 1, preferably about 0.1 to about 0.5, more preferablyabout 0.15 percent by weight relative to the total weight of reactantsThe bath pass through is conducted at such a rate as to allow thoroughcoating of the organic phase onto the aqueous phase coating on thesupport material. As the coated support material exits from the organicphase, it will be coated with the organic phase. The compounds in thetwo phases react to form the polymeric matrix.

[0109] The duration of contact between the aqueous phase coating on thesupport material and overcoat of the organic phase of sulfonyl compoundis maintained for a time sufficient to produce a dense ultrathin film ofthe matrix on the support. Depending upon the rate of the reaction, thisduration may simply be the time for the bath pass-through or it may bethe pass through plus carry time until the organic phase is subsequentlyremoved. After the matrix is formed, the membrane may be thereafterquenched and washed to remove excess reactant. The amine and/or organicphase can be metered quantitatively using coater techniques that areknown, such as, slot-die coating and gravure coating. The membrane canbe dried by application of moderate heat so that the organic liquids andoften the water solvent are evaporated. In order to prevent loss ofpermeation ability when drying is carried out, drying agents may becombined with the membrane. These agents like those described for usewith polyamides such as in U.S. Pat. No's 4,948,507; 4,983,291; and5,658,460.

[0110] Included are such agents as ammonium salts of acids, primary,secondary, and tertiary ammonium salts of acids, quaternary ammoniumsalts of acids, glycols, organic acids, saccharides, and the like.Examples include glycerin, citric acid, glycols, glucose, sucrose,triethylammonium camphorsulfonate, triethylammonium benzenesulfonate,triethylammonium toluenesulfonate, triethylammonium methane sulfonate,ammonium camphor sulfonate, and ammonium benzene sulfonate. Thisapplication can be accomplished by addition of the drying agents to oneof the solvent phases before membrane formation or by addition of thecompound directly to the membrane before or after the matrix is formed.

[0111] Flux enhancement is another membrane treatment technique that isuseful for increasing the flux of the membrane. A flux enhanceraccording to the invention can be added to either of the phases beforemembrane formation, may be added to the support material as the phasescontact each other or may be post added to the matrix. The fluxenhancers are usually low molecular weight (e.g. ≦400) amines andalcohols, which volatilize to at least some extend during the dryingstage. Their use in this fashion tends to enhance the flux ability ofthe membrane without lessening the retention value. Examples includediethylamine, ethylene diamine, triethanolamine, diethanolamine,ethanolamine, methanol, ethanol, isopropyl alcohol, guaiacol, andphenol, as well as polar aprotic solvents such as DMF, DMSO, and methylisobutylketone.

[0112] The membrane may be further processed to remove residualchemicals, adjust performance, and/or to apply a protective coating. Forexample, post formation treatment with chlorinating agents, aminemethylating agents, oxidizing agents and the like may provideperformance improvements. After such optional treatment, the membrane isready for use. The membrane may also be stored for later use.

[0113] Properties

[0114] The permeability and retention properties of the polymer matrixof the invention provide significant advantages. The permeability of thecomposite membrane of the present invention made with the polymer matrixcan be measured by its A value. Typically, the composite membranes ofthe invention have water permeability A values greater than thosereported for sulfonamide RO membranes. Preferably, either as an RO or anNF membrane, the polysulfonamide membrane of the present invention has awater permeability A value of at least about 10, preferably about 12;more preferably about 14; especially more preferably about 16 and mostpreferably about 20 when the A value is the sole parameter being used todescribe the membrane.

[0115] Preferably, the polysulfonamide membrane of the presentinvention, as an RO membrane, has a sodium chloride retention value ofat least about 98.5 percent, more preferably at least about 99 percent,especially preferably at least about 99.5 percent when the retention isthe sole parameter being used to describe the membrane.

[0116] Preferably the polysulfonamide membrane of the present invention,preferably as an RO membrane, has a combination of an A value and sodiumchloride retention that define a curve plotted as a arc of a circle withthe horizontal axis being the A value and the vertical axis being theretention value. The extreme ends of the curve are at A=1, ret=99.5 (topend) and A=12, ret=5 (bottom end).

[0117] Preferably, the polysulfonamide membrane of the invention has anA value of at least 12 and sodium chloride retention value of at leastabout 10 percent, preferably an A value of at least about 12 and NaClretention value of at least about 50 percent, more preferably an A valueof at least about 11 and an NaCl retention value of at least about 70percent, better—at least about 80 percent, best—at least about 90percent; especially preferably an A value of at least about 7 with anNaCl retention of at least about 80 percent, better—at least about 90percent, best—at least about 95 percent, more especially preferably an Avalue of at least about 5 with an NaCl retention of about 85 percent,good—at least about 90 percent, better—at least about 95 percent,best—at least about 98 percent; most preferably an A value of at leastabout 3, with an NaCl retention of at least about 85 percent, good—atleast about 90 percent, better—at least about 95 percent, special—atleast about 98 percent, best—at least about 99 percent; especially mostpreferably, an A value of at least about 1 with an NaCl retention of atleast about 90 percent, good—at least about 95 percent, better—at leastabout 98 percent, best—at least about 99 percent.

[0118] A preferred membrane of the invention has an A value in the rangeof about 1 to about 12 and a sodium chloride retention of at least about98 percent.

[0119] Another preferred membrane of the invention has an A value in therange of about 1 to about 12 and a sodium chloride retention of at leastabout 99 percent.

[0120] Preferably, the polysulfonamide membrane of the presentinvention, preferably as an NF membrane, provides magnesium sulfateretention (when tested on a 2000 ppm magnesium sulfate feed in DI water)and sodium chloride transmission values (when tested on a 2000 ppmsodium chloride feed in DI water) respectively of at least about 90percent and at least about 50 percent, preferably at least about 95percent and at least about 50 percent, more preferably at least about 90percent and at least about 70 percent, most preferably at least about 95percent and at least about 75 percent. Preferably, the A value for themembranes with these retention—transmission values has an A value of atleast about 4.5. The transmission values are measured in the samefashion and under the same conditions as the retention values.

[0121] Preferably, the polysulfonamide membrane of the presentinvention, preferably as an NF membrane, provides a sodium sulfateretention (when tested on a 2000 ppm sodium sulfate feed in DI water)and magnesium chloride transmission (when tested on a 2000 ppm magnesiumchloride feed in DI water) values respectively of at least about 90percent and at least about 30 percent, preferably at least about 95percent and at least about 30 percent, more preferably at least about 90percent and at least about 60 percent, most preferably at least about 95percent and at least about 60 percent. Preferably, the A value for themembranes with these retention - transmission values has an A value ofat least about 9.

[0122] Preferably, the polysulfonamide membrane of the presentinvention, preferably as an NF membrane, provides a sodium sulfateretention (when tested on a 2000 ppm sodium sulfate feed in DI water)and sodium chloride transmission (when tested on a 2000 ppm sodiumchloride feed in DI water) values respectively of at least about 90percent and at least about 50 percent, preferably at least about 95percent and at least about 50 percent, more preferably at least about 90percent and at least about 75 percent, most preferably at least about 95percent and at least about 75 percent. Preferably, the A value for themembranes with these retention—transmission values has an A value of atleast about 4.5.

[0123] Preferably, the polysulfonamide membrane of the presentinvention, preferably as an NF membrane, has a magnesium sulfateretention (when tested on a 2000 ppm magnesium sulfate feed in DI water)and magnesium chloride transmission (when tested on a 2000 ppm magnesiumchloride feed in DI water)values respectively of at least about 90percent and at least about 30 percent, preferably at least about 95percent and at least about 30 percent, more preferably at least about 90percent and at least about 60 percent, most preferably at least about 95percent and at least about 60 percent. Preferably, the A value for themembranes with these retention—transmission values has an A value of atleast about 9.

[0124] The composite membranes of the invention are also capable ofwithstanding exposure to strong acid such as sulfuric, hydrochloric,nitric and/or phosphoric acids. The stability can be tested by exposureof the membrane to a 20% sulfuric acid solution for 30 days at 40° C. or24 hours at 90° C. followed by testing the membrane to determine whetherthe sulfonamide backbone of the polysulfonamide has been degraded. Theintegrity of the polymer may be examined by spectroscopic techniques.The presence of sulfonic acid groups and/or amine or protonated aminegroups may be determined. Moreover, the A value and sodium chlorideretention value of the exposed membrane may be examined.

[0125] In some situations, primarily involving sulfonamide polymersderived from amine compounds having secondary amine groups as well asprimary amine groups, the acid exposure conditions the membrane so thatthe A value and sodium chloride retention value may become improved overtheir original values. Generally, the composite membranes of the presentinvention have been found to be substantially stable or preferablyexhibit improved properties under these conditions. Preferably, verysubstantially all of the membrane remains intact and especiallypreferably, essentially all of the membrane remains intact under theseconditions. Preferably, the membranes of the invention that displaysubstantial stability to strong acid conditions contain cation formingsubstituents either within their matrix polymer backbones or assubstituents pendent to the matrix polymer backbone. These membranesdisplay significant ability to separate metal ions in strongly acidicaqueous media.

[0126] The properties of the semipermeable membranes of the invention,preferably when used as NF membranes, include their capability toconcentrate metal ions contained in a strongly acidic medium. Forexample, the semipermeable membranes of the invention are capable of atleast 50% retention of copper ions and transmitting sulfuric acid whenused with a 20% sulfuric acid solution of approximately 10% coppersulfate and a flux of equal to or greater than 1 gfd and a feed solutionpressure of about 600 psi transmembrane pressure at ambient temperature(i.e. about 25° C.). Acidic solutions of iron, and other transitionmetals can also be treated in this fashion. Preferably, these membranescontain cation forming groups as discussed above.

[0127] When functioning as semipermeable membranes, the inventiondisplays a significant service life. For example, the semipermeablemembranes of the invention may operate in continuous use for at leastone month, preferably 6 months, more preferably 1 year, especiallypreferably 1 to 5 years, most preferably more than 5 yrs.

[0128] As mentioned above, the properties of ultra thinness and freedomfrom flaws or defects are goals, which will contribute to high flux andhigh retention capability of the membranes of the invention. Accordingto the present invention, the ultra thinness of the polymer matrix ismeasured as an average thickness. For the sulfonamide polymer matricesof the present invention, that average thickness ranges from about 5 nmto about 600 nm. Preferably, this average thickness ranges from about 5nm to about 400 nm. Especially preferably, this average thickness rangesfrom about 10 nm to about 200 nm and especially from about 15 to about100 nm, most especially preferably from about 15 to about 70-90 nm. Theaverage thickness is preferably measured by scanning electronmicrographs (SEM). Examples of the protocol for obtaining suchmeasurements are given in the following experimental section. Generally,for a RO membrane, small void spaces, on the order of molecular oratomic size such as from about 2 angstroms to about 50 angstroms incross sectional dimension are thought to provide the intermolecularpathways for permeation of the solute. These small intermolecularpathways are thought be curved, branched and/or of a tortuous course.They are thought to be of a physical and chemical character such thatthey prevent passage of solute. The physical character of theintermolecular pathways involves the physical dimension alone so thatpermeation occurs based upon molecular weight and three—dimensionalshape. The chemical character of the intermolecular pathways involvesthe lipophilic, hydrophilic, ionic and polar groups within theintermolecular pathway.

[0129] Generally for a NF membrane, the small void spaces thought toform the permeation pathways are believed to be slightly larger thanthose of a RO membrane. The NF membrane pathways are believed to be ofcross sectional dimension such as from about 5 angstroms to about 70angstroms. These intermolecular pathways are thought to be of a physicaland chemical character such that they allow greater permeation of onesolute relative to another. Moreover, they are believed to enableretention of similar organic molecules based upon physical (e.g.molecular size) and chemical (e.g. polarity) differences.

[0130] Matrix defects constitute large void spaces or pores or channelswithin a matrix for a RO or NF membrane. These defects in the polymermatrix are thought to affect the overall averages of intermolecularpathway size and chemical character. As a result, the defects canincrease the probability that the retention capability of the membranewill not operate at preferred values.

[0131] The term “defects” with respect to NF membranes means continuouspores, voids or free volume regions larger than about 5 nm to 10 nm intheir smallest cross sectional dimension and more preferably larger thanabout 2 nm in such dimension which substantially span the matrix incross-section.

[0132] The term “defects” with respect to RO membranes means continuouspores, voids or free volume regions larger than about 3 nm to 8 nm intheir smallest cross sectional dimension and more preferably larger thanabout 1.5 nm in such dimension, which substantially span the matrix incross section. “Substantially free” in the context of defects in eitherthe RO or NF matrix means that no more than about 2% of the volume ofthe matrix includes such defects. Very substantially free of defectsmeans that no more than about 1% of the volume of the matrix includessuch defects. Essentially free means that no more than about 0.1% of thevolume of the matrix includes such defects. The presence of defects inNF and RO membranes can be determined by the dye staining technique,described in detail below.

[0133] Consequently, the presence of void space within the membrane isboth an advantage and a disadvantage. It is an advantage becauseangstrom sized void spaces provide the interstitial pathways forpermeate passage through the matrix but can hinder the permeation ofdissolved salts or small organic molecules. It is a disadvantage whenthese void spaces become so large that they permit significant passageof a solute that is not intended to permeate. The disadvantageous voidspaces, which are believed to present large defects, may, but notnecessarily, extend completely through the matrix. These larger voidspaces may present curved, branched or wandering intermolecular pathwaysbut also may present relatively large channels passages through oralmost through the matrix. The defects may permit passage of feedsolution components such as solute that otherwise would be rejected bythe matrix. The defects also may permit coagulation of solute such thatthe matrix becomes impermeable. In particular, a defect may encompass atleast 90% of the matrix cross-section between one edge and the oppositeedge, preferably no more than 60% of this cross-sectional distance, mostpreferably no more than about 25% of this cross-sectional distance. Whenthe defects completely penetrate the matrix, even though the pathway maybe tortuous, there is a direct line for passage of the solute throughthe matrix.

[0134] Although there is a volume percent of the matrix of the inventionthat may be occupied by defects, that volume percentage is low enough toenable a high sodium salt retention for RO or is low enough to enable ahigh divalent cation salt retention for NF membranes. Under mostcircumstances, defect volume percent of the matrix of the invention isat least no more than about 10% of the total volume of the matrix. Morepreferably, the defect volume percentage is at least less than about 5%of the matrix volume. Especially preferably, the defect volumepercentage of the polymer matrix of the present invention is at leastless than about 2% of the matrix volume. Most preferably, the defectvolume percentage of the polymer matrix of the present invention is atleast less than about 1% of the matrix volume. Under preferred processand performance conditions, the matrix of the invention is preferablysubstantially free of defects, more preferably, very substantially freeof defects, most preferably essentially free of defects.

[0135] The defect size and the volume percentage of defects relative tothe matrix volume can be measured by a number of techniques. Includedare the dye stain technique described below and scanning electronmicrographs, as well as other techniques for examining macromolecularstructures.

[0136] The composite membranes made with the polymer matrices of thepresent invention have been found to display a significant improvementin A value and percent salt retention over known sulfonamide membranes.It is believed that these advantages are in part the result of the ultrathin character, density, mass per unit area and freedom from defects ofthe polymer matrices of the present invention. It is also believed thatthe application of heat during the formation of the matrix results inone or more of these advantages (e.g. improved A value). These physicalproperties translate into the differing and advantageous function forthe matrices of the present invention.

[0137] Apparatuses and Uses

[0138] The sulfonamide polymer matrices of the present invention may beformed into the composite membranes of the present invention andincorporated into filtration, separation, concentration apparatuses aswell as medical devices, blood treatment devices and the like. Thesedevices are also useful for water purification, for desalination, forindustrial waste treatment, for minerals recovery such as from themining industry, and for recovery of application solids from industrialprocessing. Further uses include layers or coatings upon the surface ofany substrate including but not limited to a porous bead, achromatographic material, a metal surfaces, a microdevice, a medicaldevice, a catheter and the like. These coatings may act as lubricants,antibiotics, reservoirs, and/or filters for agents passed over thecoated substrate. The coatings may also carry biological agents (e.g.antibodies, antibiotics, anti blood plasma coagulants, nucleotides,pharmaceuticals, and the like. The matrix may also be used toencapsulate and also to allow controlled release of pharmaceuticalagents, diagnostic agents, cosmetics, and the like.

[0139] The composite membranes of the present invention can be used inany configuration or arrangement to achieve separation of solute fromsolvent. These configurations include partition, absolute filtration,chromatography, exchange and pass through concentration as well as otherconfigurations known in the art. Although dead end filtration andchromatography configurations can be used with the composite membranesof the present invention, cross-flow filtration is preferred. Dead-endconfigurations call for passage of all solvent through the compositemembrane and retention of solute at the filtration side of the compositemembranes. The buildup of solute at the membrane surface may causecaking. In these configurations, the filtration apparatus must beperiodically back flushed in order to remove cake solids or the filterdiscarded. Cross-flow configurations involve partial pass through of thefeed liquid such that rejected solute is continually flushed away fromthe filtering membrane surface and passed with the retentate.

[0140] The polysulfonamide membranes of the present invention may beused as single sheets, multiple sheet units and may be formed in spiralwound configurations or as tubular membranes and as hollow fine fibers.In a typical configuration of a filtration apparatus containing apolysulfonamide membrane of the invention, an inert net material issandwiched between two sheets of the membrane and the sandwich unit isattached to a hollow core. The sandwich sheets are sealed at the edgesso that the net is sealed within the sandwich. The sandwich is thenwound around the hollow core with a spacer material to provide anapparatus of the desired dimension. Liquid to be filtered is deliveredunder pressure to one end of the cylinder and the retentate passes outthe opposite end of the cylinder. The permeate passes through themembranes and follows the path of the net to the hollow core where itseparately exits from the cylinder as purified permeate.

PROCEDURES, EXAMPLES AND TESTS

[0141] The following illustrative Procedures, Examples and Tests furtherillustrate the invention but are not meant to provide any limitationthereof. Unless otherwise stated, all percentages are weightpercentages.

Procedures

[0142] Mass Per Unit Area

[0143] A section of membrane made according to the invention having thedimensions of approximately 0.95 m by 0.60 m was removed of its backingmaterial, and cut into approximate 1.25 cm square pieces. The membranepieces were then placed in a cellulose thimble and loaded into a soxhletdevice equipped with a condensation tube. Dimethyl formamide (DMF) wasrefluxed for a period of 2 days, thereby dissolving the polyethersulfone(PES) support membrane and removing it from the thimble while notaffecting the polysulfonamide material. The thimble was then drained ofexcess DMF, and methyl alcohol (MeOH) was added. If any solids such asthe support material precipitated on addition of the MeOH, the MeOH wasremoved and the DMF extraction was allowed to continue for an additionalday. When no precipitation was observed upon addition of the MeOH, thethimble was extracted with MeOH for four hours using the same soxhletdevice. The thimble was then removed and dried in a convection oven at100° C. for a minimum of 15 minutes or until no MeOH odor was noticed.The extracted thin film (the matrix of the invention) was removed fromthe thimble and weighed using an analytical balance. The weight dividedby the original area provided the mass per unit area.

[0144] Density

[0145] A small amount (˜5 mg) of the matrix of the present inventionisolated using soxhlet extraction as described above was placed in a 25ml graduated cylinder of known weight with 10 ml of Isopar G at roomtemperature. Due to the density of the material relative to the densityof the Isopar G, the film remained at the bottom of the cylinder.Bromoform was then added drop-wise until the material floated to thesurface. At this point the density of the solution was determinedthrough its volume and mass; this value was termed density A. Isopar Gwas then added to the Isopar/Bromoform solution drop-wise until thematerial sank to the bottom of the cylinder. The density of this liquidsolution was again determined through its volume and mass; this value istermed density B. The average of density A and B is used as the densityof the material. The difference of densities of A and B should be lessthan 10% of the average density.

[0146] Roughness (Rms) Determination

[0147] The membrane to be imaged is analyzed in a dry state by atomicforce microscopy. A 25 to 100 μm² region of the surface is imaged incontact mode. The area imaged should be characteristic of the averagesurface structure, and absent of atypical surface features. The Rmssurface roughness is defined as:${Rms} = \left\lbrack {\frac{1}{S}{\int_{0}^{a}{\int_{0}^{b}{\left( {{f\left( {x,y} \right)} - z} \right)^{2}{x}{y}}}}} \right\rbrack^{\frac{1}{2}}$

[0148] where a and b are the lengths of each side of the image, S is thearea of the image, f(x,y) is the height at a given point (x,y), and z isthe average value of the height within the image. A standardized routineto calculate the Rms roughness is included in most commercial AFMinstruments.

[0149] SEM Thickness

[0150] The membrane (coupon) was rinsed in DI water for 30 minutes,followed by a 30 minute rinse in ethanol. The coupon was allowed to dryin air for 24 hours. The coupon was cut under liquid nitrogen with arazor, then mounted on the sample stage with the cut edge up. Sampleswere sputter coated with a 50 angstrom Pt coating and imaged. Thicknessmeasurements were made at locations where cracks in the thin filmallowed the edge to be seen. Three such areas were averaged to providethe SEM thickness.

[0151] Defects Per Unit Area

[0152] A soluble dye that will stain the support membrane, but not thethin film, is chosen. For most polysulfonamide membranes on PES orpolysulfone (PS) supports, a solution of Acid Red Dye #4 (5%) in MeOH(25%) and DI water (70%) is effective. The solution is prepared andapplied to the active side of the membrane. Due to the adsorptivecharacter of the dye, it will stain the supporting membrane madeaccessible by defects but not the polysulfonamide thin film. Thus,regions in the film with defects large enough to permit passage of thedye can be visually observed as red dots. The number of defects per unitarea can then be determined through counting or image analysis of thered dots.

[0153] Since defects are often localized in groups as a result of poormanufacturing technique, it is important to select an area not includingsuch groups. This selection technique will provide an assessment of themembrane's inherent number of defects.

[0154] Permeation and Retention Procedures (A and Retention Values)

[0155] The permeation and retention characteristics of the membranes ofthe invention may be determined using the test conditions providedhereinabove. Conditions useful for reference are also found in ASTMdesignation D4194-95 and D4516-85 entitled “Standard Test Methods forOperating Characteristics of Reverse Osmosis Devices” and “StandardPractice for Standardizing Reverse Osmosis Performance Data”respectively.

EXAMPLES Example 1

[0156] Effect of Reaction Time on Membrane Performance

[0157] A sample of HW31 UF membrane (Osmonics, Inc, Minnetonka, Minn.,USA) was rinsed in DI water for 30 minutes. Surface water was removedwith an air knife. An aqueous amine solution [1.0% ethylene diamine(EDA), 6.6% triethylammonium camphorsulfonate (TEACSA), and 0.1%dimethylaminopyridine (DMAP); 100 g total] was poured onto the activeside of the support and allowed to remain in contact for one minute. Theexcess was drained off and an air knife was used to meter the remainingamine. An organic solution (0.16% naphthalenetrisulfonyl chloride(NTSC), 4.34% monoglyme, in 100 ml IsoparG) was then applied to theactive side and allowed to remain in contact for a given time. Theexcess was then drained off and the resulting material was placed in anoven at 100° C. for 6 minutes.

[0158] Three coupons were cut from each membrane and placed in membranetest cells. Coupons were tested at 225 psig for four hours and then theA-Value and the sodium chloride passage (tested on a 2000 ppm sodiumchloride in DI water feed) were determined. The best single coupon fromeach set was used as the representative performance for that membrane.Results are shown in the following Table. Time (minutes) A Value SodiumChloride Passage 0.5 9.50 8.64 1.0 7.00 6.02 2.0 4.90 7.90 5.0 2.70 7.7030.0 1.30 9.00 60.0 1.70 13.70

Example 2

[0159] Effect of Oven Drying on Membrane Performance

[0160] Membranes were prepared as described in Example 1, except afterthe excess organic solution was drained off, the resulting material waseither evaporated with moving air (air dried) or placed in an oven(100°C.) for 6 minutes (oven dried).

[0161] Three coupons were cut from each membrane and placed in membranetest cells. Coupons were run at 225 psig for four hours and then theA-Value and the sodium chloride passage (tested on a 2000 ppm sodiumchloride in DI water feed) were determined. The best single coupon fromeach set was used as the representative performance for that membrane.Results are shown in the following Table. A-Value A-Value NaCl PassageNaCl Passage Time (Air Dried) (Oven Dried) (Air Dried) (Oven Dried) 0.562.4 9.5 87.2 8.64 1.0 26.3 7.0 53.2 6.02 2.0 27.6 4.9 45.5 7.90 5.011.4 2.7 34.2 7.70 30.0 6.2 1.3 57.4 9.00 60.0 3.5 1.7 34.8 13.70

Example 3

[0162] Effect of Membrane Thickness on Performance

[0163] Membranes were prepared as described in Example 1. Three couponswere cut from each membrane and placed in membrane test cells. Couponswere run at 225 psig for four hours and then the A-Value and the sodiumchloride passage (tested on a 2000 ppm sodium chloride in DI water feed)were determined. The best single coupon from each set was used as therepresentative performance for that membrane. Results are shown in thefollowing Table. The SEM thickness was measured using the generalprocedure described above. Average Time A-Value NaCl Passage Thickness(nm) 0.5 9.5 8.64 42.6 1.0 7.0 6.02 45.0 2.0 4.9 7.90 54.3 5.0 2.7 7.7093.0 30.0 1.3 9.00 93.5 60.0 1.7 13.70 108

Example 4

[0164] Effect of Conditions on Roughness

[0165] A sample of HW31 UF membrane was rinsed in DI water for 30minutes. Surface water was removed with an air knife. The desired aminesolution (100 ml in DI water) was poured onto the active side of thesupport and allowed to remain in contact for one minute. The excess wasdrained off and an air knife used to meter the remaining amine. Theorganic solution (0.16% NTSC, 4.34% monoglyme, in VM&P naphtha) wasapplied to the active side and allowed to remain in contact for oneminute. The excess was then drained off and the remaining solutionevaporated with moving air. Samples were dried by 2 day ambientevaporation. Amine solution 1 Amine solution 2 Amine solution 3 1% EDA1% EDA 1% EDA 0.1% DMAP 0.1% DMAP 6.6% TEACSA Roughness Results AmineSolution Roughness Rms (nm) 1 52.37 2 26.6 3 3.25

Example 5

[0166] Membrane Made Without Heat

[0167] An aqueous solution of ethylenediamine (1.0% by weight) andN,N-dimethylaminopyridine (0.1% by weight) was poured onto the uppersurface of a PES support membrane (Osmonics HW31). This solution wasallowed to remain in contact with the support for 30 seconds, afterwhich time, the excess fluid was drained and metered with an airknife.An organic solution comprising 1,3,6-naphthalenetrisulfonyl chloride(0.16% by weight) and monoglyme (4.3% by weight) in IsoparG was thenpoured on top of the metered aqueous solution. This organic solution andthe aqueous solution were allowed to remain in contact with each otherfor 30 seconds before the excess organic solution was drained andevaporated with an airknife. Following this, the membrane was allowed tostand for 30 minutes to evaporate any remaining organic solution.

[0168] The membrane was tested on a variety of salt feeds (2000 ppm) todetermine performance. The following table shows performance data forthe membrane made in example 5 on MgSO₄, Na₂SO₄ and MgCl₂ feedsolutions. Example 5 Membrane Performance 2000 ppm salt feed A val %salt passage MgSO₄ 9.0 4.7 Na₂SO₄ 13.5 2.4 MgCl₂ 13.1 62.8

Example 6

[0169] Membrane Prepared on a Coater

[0170] A roll of water wet support membrane (Osmonics HW31) wascontinuously passed through an aqueous solution containing 60% technicalgrade triethylenetetraamine (1.0% TETA by weight), triethylammoniumcamphorsulfonate (6.6% by weight) and N,N-dimethylaminopyridine (0.1% byweight) and metered with an air knife. The active side of the webintermediate (side with aqueous solution coating) was then contactedwith an organic solution of 1,3,6-naphthalenetrisulfonyl chloride (0.16%by weight) and monoglyme (4.3% by weight) in IsoparG. The membrane wasthen passed through a 120° C. convection oven for a 2-6 minute timeperiod.

[0171] The membrane was tested on a variety of salt feeds (2000 ppm) todetermine performance. The following table shows performance data forthe membrane made in example 6 on MgSO₄, Na₂SO₄ and MgCl₂ feedsolutions: Example 6 Membrane Performance 2000 ppm salt feed A val %salt passage NaCl 4.5 78.8 MgSO₄ 5.3 2.1 Na₂SO₄ 5.6 5.0

Example 7

[0172] Membrane Made With Heat

[0173] An aqueous solution of ethylene diamine (1.0% by weight),N,N-dimethylaminopyridine (0.1% by weight) and triethylammoniumcamphorsulfonate was poured onto the upper surface of a PES supportmembrane (Osmonics HW31). This solution was allowed to remain in contactwith the support for 1 min, after which time, the excess fluid wasdrained and metered with an airknife. An organic solution comprising1,3,5-benzenetrisulfonyl chloride (0.16% by weight) and monoglyme (4.3%by weight) in IsoparG was then poured on top of the metered aqueoussolution. The organic solution and the aqueous solution were allowed toremain in contact with each other for 1 minute before the excess organicsolution was drained and metered with an airknife. Following this, themembrane was dried in a 100° C. oven for 6minutes.

[0174] The membrane was then tested on a NaCl feed solution (2000 ppm).

Example 8

[0175] Membrane Made with Heat

[0176] A membrane was prepared and tested according to example 7 withthe following changes. The organic solution was1,3,6-naphthalenetrisulfonyl chloride (0.16 by weight) and monoglyme(4.3% by weight) in IsoparG. The following table shows performance datafor the membranes made in Example 7 and Example 8: Membrane PerformanceA val % NaCl passage Example 7 (0.16% BTSC) 3.2 1.0 Example 9 (0.16%NTSC) 7.7 1.5

Example 9

[0177] Membrane Made On A Coater

[0178] A membrane was prepared according to Example 6 with the followingexceptions. The aqueous phase consisted of ethylene diamine (1.0% byweight), triethylammonium camphorsulfonate (6.6% by weight),N,N-dimethylaminopyridine (0.1% by weight), isopropyl alcohol (20% byweight) and sodium carbonate (0.2% by weight).

[0179] The membrane was tested on a NaCl salt feed (2000 ppm) todetermine performance.

Example 10

[0180] Membrane Made on a Coater

[0181] A membrane was prepared and tested according to example 9 withthe following exceptions. The aqueous phase consisted of ethylenediamine (1.0% by weight), triethylammonium camphorsulfonate (6.6% byweight) and N,N-dimethylaminopyridine (0.1% by weight). The organicsolution was comprised of 1,3,5-benzenetrisulfonyl chloride (0.14% byweight) and monoglyme (4.3% by weight) in IsoparG.

[0182] The following table shows performance data for membrane made inexamples 9 and 10. Membrane Performance A val % NaCl passage Example 911.1  8.7 Example 10 14.7 31.1

Example 11

[0183] Membrane Made With Drying Agent

[0184] An aqueous solution of ethylene diamine (1.0% by weight),N,N-dimethylaminopyridine (0.1% by weight) and triethylaminecamphorsulfonate (6.6% by weight) was poured onto the upper surface of aPES support membrane (Osmonics HW31). This solution was allowed toremain in contact with the support for 1 minute, after which time, theexcess fluid was drained and metered with an airknife. An organicsolution comprising 1,3,6-naphthalenetrisulfonyl chloride (0.16% byweight) and monoglyme (4.3% by weight) in IsoparG was then poured on topof the metered aqueous solution. This organic solution and the aqueoussolution were allowed to remain in contact with each other for 1 minutebefore the excess organic solution was drained and evaporated with anairknife. Following this, the membrane was dried in an oven for 6minutes at 100 deg C.

[0185] The membrane was tested on a NaCl feed (2000 ppm) to determineperformance.

Example 12

[0186] Membrane with Drying Agent and Amine Post Treatment to IncreaseMembrane Flux

[0187] Membrane was prepared according to Example 11 with the followingchanges. After airknife evaporation of the organic, a solution ofdiethanolamine (10% by weight) in methanol was poured onto the membranesurface. This was allowed to contact the membrane for 30 seconds, afterwhich time the excess fluid was drained. The membrane was then dried andtested as outlined in Example 11.

[0188] The following table shows performance results from membrane madein examples 11 and 12: Membrane Performance A val % NaCl Pass Example 11(control)  4.9  5.3 Example 12 (amine post treatment) 17.4 49.6

Example 13

[0189] Membrane with Drying Agent

[0190] Membrane was prepared and tested according to Example 11 with thefollowing changes. The support membrane used was a PS ultrafiltrationmembrane (20% binary w/DMF cast 2 mil thick on a polyester backing, at30 fpm into 18.5C DI water) with an A val of 100 and MWCO of 11K (90%dextran retention). The amine phase was an aqueous solution of ethylenediamine (3.0%), N,N-dimethylaminopyridine (0.1% by weight) andtriethylamine camphorsulfonate (6.6% by weight). The organic solutionwas allowed to remain in contact with the aqueous solution for 2minutes. After pouring off the organic phase, the membrane was placedinto an oven and dried for 6 minutes at 100 deg C.

Example 14

[0191] Membrane with Drving Agent and Alcohol

[0192] Membrane was prepared and tested according to Example 13 with thefollowing changes. The amine phase was an aqueous solution of ethylenediamine (3.0%), N,N-dimethylaminopyridine (0.1% by weight),triethylamine camphorsulfonate (6.6% by weight) and isopropyl alcohol(10% by weight).

Example 15

[0193] Membrane with Drying Agent and Alcohol

[0194] Membrane was prepared and tested according to Example 13 with thefollowing changes. The amine phase was an aqueous solution of ethylenediamine (3.0%), N,N-dimethylaminopyridine (0.1% by weight),triethylamine camphorsulfonate (6.6% by weight) and isopropyl alcohol(20% by weight).

[0195] The following table shows performance results for membranes madein examples 13, 14, and 15: Membrane Performance A val % NaCl PassExample 13 (Control) 4.7  9.8 Example 14 (10% IPA) 7.4 11.7 Example 15(20% IPA) 9.0 11.9

[0196] All publications, patents, and patent documents are incorporatedby reference herein, as though individually incorporated by reference.The invention has been described with reference to various specific andpreferred embodiments and techniques. However, it should be understoodthat many variations and modifications may be made while remainingwithin the spirit and scope of the invention.

What is claimed is:
 1. A sulfonamide polymer matrix having an averagethickness of from about 5 nm to about 100 nm, wherein the polymer matrixis composed of sulfonyl compound residues having at least two sulfonylmoieties and amine compound residues having at least two amine moieties2. The polymer matrix of claim 1 wherein the amine compound residue isnot polyethylenimine having a molecular weight of greater than or equalto 600 daltons.
 3. The polymer matrix according to claim 1, having athickness of from about 15 nm to about 100 nm.
 4. The polymer matrixaccording to claim 1, having a mass/area ratio of from about 20 mg/m² toabout 200 mg/m².
 5. The polymer matrix according to claim 1, having amass/area ratio of from about 50 mg/m² to about 150 mg/m².
 6. Thepolymer matrix according to claim 1, having no more than 5 percent ofthe matrix volume as defects.
 7. The polymer matrix according to claim1, which comprises sulfonyl compound residues derived from a sulfonylcompound of formula I: X—SO₂—Z—(SO₂—X)_(n)  I wherein each X is aleaving group, Z is an organic nucleus comprising 1 to about 30 carbonatoms, and n is an integer from 1 to
 5. 8. The polymer matrix accordingto claim 7 wherein the organic nucleus contains one or more heteroatoms.9. The polymer matrix according to claim 7 wherein Z is C₁-C₁₈alkyl,C₂-C₁₈alkenyl C₃-C₇cycloalkyl, C₄-C₁₆alkylcycloalkyl, C₃-C₇cycloalkenyl,C₄-C₁₆alkylcycloalkenyl, C₆-C₁₄aryl, C₆-C₁₀aryl-C₁-C₈alkyl, or (C₆-C₁₀)aryl-C_(1 -C) ₈alkyl-(C₆-C₁₀)aryl.
 10. The polymer matrix according toclaim 1, which comprises amine compound residues derived from a compoundof formula II: R¹—NH—Y—[(CH₂)_(j)(NH—R²)]_(m)  IIwherein Y is an organicnucleus; each R¹ and R² is independently hydrogen, an aliphatic group,or an aromatic group; m is 1, 2, or 3; and j is zero or an integer from1 to about
 10. 11. The polymer matrix according to claim 10, wherein Yis C_(1-C) ₁₈alkyl, C₂-C₁₈alkenyl, C₃-C₇cycloalkyl,C₄-C₁₆alkylcycloalkyl, C₃-C₇cycloalkenyl, C₄-C₁₆alkylcycloalkenyl,C₆-C₁₀aryl, C₆-C₁₀aryl-C₁-C₈alkyl, (C₆-C₁₀)aryl-C₁-C₈alkyl-(C₆-C₁₀)aryl,C₁-C₁₈—NHR³C₁-C₁₈ alkyl, or C₁-C₁₈—NHR³; and R³ is hydrogen,C₁-C₈alkoxy, C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₃-C₈cycloalkyl,C₃-C₈cyclo-alkenyl, C₄-C₂₀alkylcycloalkyl, C₄-C₂₀alkylcycloalkenyl,C₆-C₁₀aryl, or C₆-C₁₀aryl-C₁-C₈ alkyl.
 12. The polymer matrix accordingto claim 1, which comprises sulfonyl compound residues derived from asulfonyl compound having at least two activated sulfonyl groups and anorganic nucleus, and which comprises amine compound residues derivedfrom an amine compound having at least two primary and/or secondaryamine groups and an organic nucleus.
 13. The polymer matrix according toclaim 12 wherein the sulfonyl compound residues are selected from thegroup consisting of benzene disulfonyl residue, benzene trisulfonylresidue, naphthalene disulfonyl residue, naphthalene trisulfonylresidue, anthacenyl disulfonyl residue, anthracenyl trisulfonyl residue,pyridine disulfonyl residue and any combination thereof.
 14. The polymermatrix according to claim 12 wherein the amine compound residues areselected form the group consisting of ethylenediamine residue,diethylene triamine residue, tris-(2-aminoethyl)methane residue,tris-(2-aminoethyl)amine, 1,3-propanediamine, butanediamine,pentanediamine, hexanediamine, triethylenetetramine, (aminoalkyl)₁₋₄arylresidue, meta-xylene diamine, and 2-hydroxy-1,3-diaminopropane, and anycombination thereof.
 15. A combination comprising a sulfonamide polymermatrix according to claim 1 coated on a support material.
 16. Acomposite membrane comprising a sulfonamide polymer matrix according toclaim 1 on a porous support material.
 17. The membrane of claim 16wherein the porous support material has a molecular weight cut-off asmeasured by the ASTM method at 90% dextran rejection of less than 30,000Daltons.
 18. The membrane of claim 16 which has an A value greater thanor equal to 2, and a sodium chloride retention value of greater thanabout 85%.
 19. The membrane of claim 16 having an A value of at least 7and at least 98.5% NaCl retention.
 20. The membrane of claim 16 havingan rms roughness less than
 10. 21. The polymer matrix of claim 1 whichhas been subjected to post-form ation treatment with a chlorinatingagent, an amine, a methylating agent, or an oxidizing agent.
 22. Themembrane of claim 16 which has been subjected to post-formationtreatment with a chlorinating agent, an amine, a methylating agent, oran oxidizing agent.